In the conventional manufacturing for the semiconductor or solar cell, the method of using a gas dopant or a doped slurry when a p-type or n-type impurity diffusion layer is formed in the semiconductor substrate has been proposed. However, a barrier layer needs to be formed on the non-diffusion side for high temperature thermal diffusion using the above existing gas dopant or doped slurry, thereby resulting in a lengthy and complex process, and correspondingly increasing the costs. If an ion implantation method is used, both the required equipment costs and maintenance costs are high. Furthermore, it is difficult to achieve a powerful balance between the performances and costs of the existing slurry, so that it is non-competitive in the solar cell industry (reference [1]).
In particular, in the manufacturing process of two-sided cells in which both sides can generate power by receiving light, in the process of enabling the p-type and n-type impurities to diffuse into the semiconductor substrate used in the solar cells to form the impurity diffusion layer, different processes are used for the p-type impurity diffusion layer and the n-type impurity diffusion layer respectively. However, such a method has the problem of increasing steps. To solve these problems, a simpler method is proposed for forming a n-type impurity diffusion layer using a part of thermal processing products of the p-type impurity diffusion composition as a mask, after providing the p-type impurity diffusion composition containing a receptor element on the semiconductor substrate and forming the p-type impurity diffusion layer by thermal processing.
Furthermore, the gas dopant is generally a highly toxic substance, such as boron tribromide, phosphorane, or phosphorus oxychloride, has high requirements for pipes and tail gas absorption equipment, and it is likely to have a major accident in case of leakage, and pollutes the surrounding environment.
Patent Document [1]: Wei Qingzhu, Lu Junyu, Lian Weifei, Ni Zhichun, N-type double-sided battery and manufacturing method therefor: China, CN201510020649.4 [P]. 2015-01-15 [1].